1. Field of the Invention
The present invention relates to a process for the preparation of antimicrobial polymers by polymerization of tert-butylaminoethyl methacrylate, and the use of the antimicrobial polymers. More particularly, the invention relates to a process for the preparation of antimicrobial polymers by graft polymerization of tert-butylaminoethyl methacrylate on a substrate, and the use of the antimicrobial polymers.
2. Description of the Background
The colonization and spread of bacteria on surfaces of pipelines, containers or packaging is highly undesirable. Layers of slime often form, which allow the microbe populations to rise to extreme levels, lastingly impairing the quality of water, drinks and foodstuffs, and can even lead to decay of the goods and damage to the health of consumers.
Bacteria are to be kept away from all areas of life where hygiene is of importance. Since textiles directly contact the body, and, in particular the genital area, and are used for the care of the sick and elderly, textiles should be freed of bacteria. Bacteria should also be kept away from the surfaces of furniture and equipment in nursing wards, in particular in the intensive care and infant care sector, in hospitals, especially in rooms for medical operations, and in isolation wards for critical cases of infection, as well as in toilets.
Equipment, and surfaces of furniture and textiles are currently treated to ward against bacteria as required or also preventively with chemicals or solutions and mixtures thereof which act as disinfectants, such having a more or less broad and powerful antimicrobial action. Such chemical compositions have a nonspecific action, are often themselves toxic or irritating, or form degradation products which are unacceptable to health. Intolerances are often also found in appropriately sensitized persons. Another procedure which is used to inhibit the spread of bacteria on surfaces is to incorporate antimicrobially active substances into a matrix.
Tert-butylaminoethyl methacrylate is a commercially available monomer of methacrylate chemistry and is employed in particular as a hydrophilic monomer in copolymerizations. Thus, EP 0 290 676 describes the use of various polyacrylates and polymethacrylates as a matrix for immobilization of bactericidal quaternary ammonium compounds.
U.S. Pat. No. 3,592,805 discloses the preparation of systemic fungicides in which per halogenated acetone derivatives are reacted with methacrylate esters, such as, for example, tert-butylaminoethyl methacrylate.
U.S. Pat. No. 4,515,910 describes the use of polymers of hydrogen fluoride salts of aminomethacrylates in dental medicine. The hydrogen fluoride bonded in the polymers emerges slowly from the polymer matrix and is said to be effective against caries.
In another technical field, U.S. Pat. No. 4,532,269 discloses a terpolymer of butyl methacrylate, tributyltin methacrylate and tert-butylaminoethyl methacrylate. This polymer is used as an antimicrobial paint for ships, the hydrophilic tert-butylaminoethyl methacrylate promoting slow erosion of the polymer and in this way liberating the highly toxic tributyltin methacrylate as an antimicrobially active compound.
In these applications, the copolymer prepared with aminomethacrylates is only a matrix or carrier substance for added microbicidal active compounds, which can diffuse or migrate out of the carrier. Polymers of this type lose their action at a faster or slower rate when the necessary "minimum inhibitory concentration" (MIC) is no longer achieved on the surface.
EP 0 204 312 describes a process for the preparation of antimicrobially treated acrylonitrile fibers. The antimicrobial action is based on a protonated amine as a comonomer unit, dimethylaminoethyl methacrylate and tertbutylaminoethyl methacrylate, inter alia, being used as protonated species. However, the antimicrobial action of protonated surfaces is severely reduced after loss of the H(+) ions. A need continues to exist for an effective method of providing surfaces of objects with antimicrobial properties.